What is the loadView method used for in a controller?

The loadView method in an iOS controller is used to create and configure the controller's main view programmatically, without using a Storyboard or XIB files. By default, if the controller is loaded from a Storyboard, this method is not called, but if you want to fully control the creation of the view, you override loadView and assign the desired UIView object to the view property.

Example of overriding:

override func loadView() {
    let customView = UIView()
    customView.backgroundColor = .white
    self.view = customView
}

If you do not override loadView, the system will load the view from a Storyboard or XIB, or create an empty UIView by default.